1. Field of the Invention
The present invention relates to a system for maintenance and diagnosis of mobile telephone equipment and more particularly to a system of this type which is adapted for efficient and economic maintenance and diagnosis of mobile telephone equipment carried on a vehicle, such as a car, ship, airplane or the like.
For example, small scale car telephone services using ten channels at the most within a 150 MHz frequency band started in 1949 in St. Louis in the United States. Thereafter, with the 1971 earthquake which hit the suburbs of Los Angeles, car telephone equipment was put into practice in large scale and this was followed by enlargement of capacity and reduction of size and weight of the equipment by introducing digital technology and utilizing microcomputers and LSI technology.
2. Description of the Prior Art
Considering car telephone services as an example of the mobile telephone services, these services have already been commercialized in large cities in Japan. In the United States, too, the car telephone services are today under field tests and on the verge of commercialization in the near future. Further, in other countries, efforts have been made to research, develop and put into practice the car telephone services and, like general telephone services, they are expected to come into wide use in the future.
Mobile telephone equipment for car telephone services are carried on a car of each subscriber and they can be moved here and there to perform desired telephone communication (talking). In the event of a failure of talking, for example, the subscriber claims or declares such a failure. In response thereto, maintenance and diagnosis of the mobile telephone equipment must be performed without dismantling the equipment from the car.
According to conventional maintenance and diagnosis, a service engineer carries an instrument dedicated to maintenance with him to the car carrying the defective equipment so as to perform maintenance and diagnosis in accordance with the following procedures:
(1) Operations as claimed by the subscriber are repeated to confirm reappearance of abnormal states;
(2) When, in effect, abnormal states as claimed by the subscriber are confirmed, the instrument for maintenance is connected to the mobile telephone equipment and various commands are inputted thereto to check various response signals, thereby confirming presence or absence of faults and faulty locations;
(3) Faulty locations are adjusted or repaired and faulty parts or units are exchanged with new ones and thereafter, recovery to normal states is confirmed and the repaired equipment is handed over to the subscriber; and
(4) The faulty parts or units are brought back to a maintenance center for precise diagnosis and repairs.
The above procedures tell the fact that particularity of the equipment carried on the vehicle burdens the service engineer with heavy labor and besides, a fairly sophisticated and large-sized instrument for maintenance is required. Therefore, for future development of such services, efficient and economic maintenance and diagnosis of the mobile telephone equipment are desired.